Add new type into metrics_constants.proto

* Change DIALOG_UPDATABLE_LIST_PREFERENCE to DIALOG_SWITCH_A2DP_DEVICES.
* Add DIALOG_SWITCH_HFP_DEVICES
* This is for a new dialog which is able to update content instantly when connected devices change

Bug: 77783217
Test: build
Change-Id: I1dd79f35a2b26be071acceca5fe984c8f17d44ec